1. Field of the Invention
The subject invention relates to an apparatus and method for high speed optical inspection of fluids, such as liquid pharmaceutical products that may be stored in syringes, vials or other such containers.
2. Description of the Related Art
Liquid pharmaceutical products must be manufactured and packaged under carefully controlled conditions to prevent extraneous material from being incorporated into the finished product. Despite these careful manufacturing and packaging controls, most pharmaceutical companies perform a final optical inspection in an effort to identify any extraneous material that might have been incorporated inadvertently into the sealed container of the liquid pharmaceutical product. Such optical inspections are intended to identify any undissolved granular material, fibers or the like.
A typical prior art optical inspection apparatus for these purposes includes a small video camera directed at the container of liquid pharmaceutical. The camera is connected to a video monitor which displays a magnified and illuminated image of the liquid pharmaceutical in the container. The image displayed on the monitor enables an inspector to identify containers of the liquid pharmaceutical products with extraneous materials. These packages then can be rejected and discarded. Additionally, the inspection apparatus may be used to identify sources of contamination. Corrective measures then may be incorporated into the manufacturing and packaging process.
The optical inspection of liquid pharmaceutical products typically is carried out for each packaged product, and not merely for a representative sample. Accordingly, the inspection must be carried out very quickly. A typical optical inspection is performed with an apparatus that rapidly advances a container into the viewing field of the camera, temporarily interrupts the movement of the apparatus to enable an optical inspection and then quickly moves the container to a location for further packaging or to a location for discard.
Extraneous material in a liquid pharmaceutical product will tend to settle at the bottom of the container, and there is a substantial risk that the inspection method will not detect a small extraneous particle that has settled to the base of the container. Prior art optical inspection devices have recognized the problems associated with the settling of extraneous matter in liquid pharmaceuticals. Thus, prior art devices have included mechanisms to move any extraneous matter from the bottom of the container into a more central position in the container where optical inspection is more accurate and reliable. For example, one prior art apparatus is operative for quickly inverting the container immediately prior to the optical inspection. This inversion is intended to cause any extraneous material to move gravitationally within the liquid from a location spaced from the location that had originally defined the gravitational bottom of the container. The extraneous material can be observed due to its movement and to its location in a more central position in the container.
Other prior art inspection devices spin the container of the liquid pharmaceutical product about a vertical axis. The spinning of the container causes extraneous material in the liquid pharmaceutical product to move from its settled location adjacent the bottom of the container to a location spaced from the bottom of the container. This movement of the extraneous material and the more central location of the extraneous material facilitates the optical inspection process and improves accuracy of inspections.
Both of the prior art devices for generating movement of extraneous material in liquid pharmaceuticals perform their intended function well, but have certain drawbacks. In particular, the prior art apparatus for inverting the container or for spinning the container is fairly complex and requires a substantial amount of space on the inspection apparatus. Thus, machines to perform these optical inspections are undesirably large and take up valuable space in the manufacturing or packaging facility. Additionally, the potential exists for damaging portions of the container during the inversion or spinning. In this regard, some such containers are small flexible plastic containers that have a small needle cannula pre-mounted thereon. The container may be formed from a flexible material that permits injection by squeezing opposite walls of the container. These small flexible containers with small needle cannulas can be damaged by the rapid inversion or spinning. Furthermore, inversion and spinning both take time, thereby slowing the inspection process.
In view of the above, it is an object of the subject invention to provide an inspection apparatus that enables accurate optical inspections that are capable of detecting extraneous materials in liquid solutions.
It is another object of the subject invention to provide an inspection apparatus that enables extraneous materials in liquid solutions to move without spinning or inverting the containers of these solutions.
The subject invention is directed to an inspection apparatus for optically inspecting liquid solutions. The apparatus may include an indexable fixture for receiving containers of a liquid solution to be inspected and for sequentially indexing the containers into a location for inspection. The apparatus may further include loading means for selectively loading the containers into the indexable fixture. The loading means may be automated and high speed and may be constructed to ensure accurate positioning of the containers in the fixture. The apparatus may further include at least one optical inspection station at one or more locations in proximity to the indexable fixture. The optical inspection station may include at least one light source and at least one video camera. The video camera may be connected electronically to a video monitor that provides a video display of a container that is indexed into the inspection station.
The apparatus of the subject invention further includes at least one vibrator in proximity to the indexable fixture. The vibrator is operative to generate vibrations that are sufficient to agitate the liquid solution in the container and to generate movement of any extraneous material in the liquid solution. The amplitude and frequency of vibration may be selected in accordance with characteristics, such as viscosity of the liquid solution being inspected. In some embodiments, the vibrator may be variable so that the frequency and amplitude can be adjusted. Additionally, the vibrator may be intermittently operative. In particular the vibrator may be terminated after a selected time based on the indexing of the fixture, or the vibrator may be terminated in response to a signal from a technician using the apparatus. The termination of the vibration will permit the technician to observe a stationary container. However, any extraneous material in the liquid solution will remain in motion despite the termination of the vibration, and hence will be readily observable.
The apparatus may include means for identifying unacceptable containers for discard. The apparatus may further include means for ejecting containers that have been identified as unacceptable. Finally, the apparatus may include means for advancing acceptable containers from the indexable fixture to a location for further packaging or use.
The apparatus of the subject invention provides several significant advantages over the prior art. In particular, the vibrator can be small and can be spaced at least a small distance from the container to be inspected. Thus, the entire apparatus can be more compact than an apparatus that relies upon inversion or spinning of the container, or other such prior art apparatus that requires complex mechanisms to be incorporated into the fixture for generating such movement. Additionally, the minor vibration enabled by the subject apparatus is less likely to damage fragile containers or needle cannulas. Furthermore, the vibration does not add significantly to the inspection cycle time. Finally, vibration amplitude and frequency can be selected to generate movement of extraneous particles without generating bubbles or excessive turbulence that could give rise to false indications of extraneous materials. Bubbles or turbulence could be generated, however, by the prior art apparatus that rapidly inverts or spins the container.